Waste wood structural columns

There is an incredible amount of “waste” wood that is thrown into landfills or otherwise left to rot because it is not long enough to be used vertically in a building. So we take that wood and stack it up to make load bearing columns in buildings. Offcuts from log home factories, discarded 2x4s and 2x6s and dead tree limbs all find permanent, structural homes in our waste wood columns.

Presentation

Tire pier foundation

Used car and truck tires are a waste dilemma in our society. Why not put these tires to use as structural elements in our buildings? We have used tires to create a tire pier foundation, creating a strong, long-lasting foundation that cost very little to make!

Presentation

Prefabricated straw bale walls

Endeavour has a long history of working with prefabricated straw bale wall panels. We were the first to make panels in 2000, and have continued to implement versions of panelized straw bale systems in residential and commercial building. To date, we have been involved in over 20 prefab straw bale projects!

Straw bale walls have a remarkable array of benefits, but they can be labour intensive and are difficult to build in a mainstream context. By prefabricating the plastered straw bale panels, they can be delivered to a job site for the same cost as conventional framed walls, and still have all the environmental benefits. And they can be produced quickly and easily in small, local micro-factories, making it possible to bring the benefits of bale walls to any region.

Round straw bale columns

Many people use small, square straw bales to make buildings, but we used the big round bales as load-bearing columns in a building! The big rounds are incredibly dense and uniform, and we lab tested them to 120,000 pounds of load! They are quickly and easily assembled and make a truly sustainable “frame” for a building.

Presentation

This is one in a series of blog posts about the materials we’ve chosen to build our Zero House project…

What are BiPVco Flextron solar modules? BiPVco specializes in the manufacturing of building integrated photovoltaics, that is, solar modules that are a part of the building, rather than “add-ons” that must be fastened over or onto the building.

Where are BiPVco Flextron solar modules used in Zero House? The standing seam metal roof on the south side of the building receives 32 modules that each produce 120 watts of power, for a total of 3,840 watts (3.84 kW). We use a company that does sheet metal fabrication Texas. These parts are hand delivered to us.

How do BiPVco Flextron solar modules help achieve the Zero House goals?

Zero net energy use – The solar energy harvested from the BiPVco modules over the course of a year will equal the amount of energy it takes to operate Zero House.

Zero carbon footprint – The modules use a flexible, CIGS thin-film technology that does not require the tempered glass or aluminum frames of typical modules, and combined with the elimination of mounting racks, the BiPVco modules have a significantly smaller carbon footprint than other solar modules (67 kgCO2e/m2 versus 242 kgCO2e/m2 for monocrystalline modules, according to the Inventory of Carbon and Energy V.2).

Zero waste – The flexible modules are highly resilient and require only a fraction of the packaging for glass-covered modules.

Durability – We don’t need to make any penetrations in the roof surface to mount the BiPVco modules, which is a huge advantage in terms of long-term durability of the roof. There is also no glass to break in case of hail or falling tree branches.

Affordability – The modules are comparable in price per watt to standard modules, but the savings on racking and mounting make them a very attractive option price-wise. Roof trusses do not need to be sized to take an extra load, as the modules are very light weight and don’t present any wind uplift issues.

Prefab – We can mount the modules to the roofing and ship them together to the building site, eliminating a separate shipping step and construction step on site.

Code compliance – BiPVco does not yet have CSA certification, and requires a field inspection.

Any drawbacks to using BiPVco solar modules?

The adhesive that binds the modules to the metal roofing seems very strong, but only time will tell how it holds up the Canadian climate.

This is one in a series of blog posts about the materials we’ve chosen to build our Zero House project…

What is 475 High Performance Building Supply? 475 High Performance Building Supply provides essential building knowledge and components to building professionals, focusing on materials that provide the best air tightness, ventilation and durability.

Mento 1000 exterior housewrap

Tescon Vanna tape provides a great seal for air barriers

Extoseal is a flexible tape for making water tight window sills

Intello Plus is a smart vapor control membrane

The exterior of Zero House all wrapped up in Mento 1000

Where are 475 products used in Zero House? There are 475 High Performance Building Supply products used throughout the Zero House building, including:

Mento 1000 house wrap – A 3-layer airtight, vapor-open housewrap that is an extremely strong weather resistive barrier (WRB). It provides superior weather protection and can cover most exterior building substrates. It has an actively vapor open, monolithic layer of TEEE film that is extremely waterproof – and outperforms perforated/stretched WRBs both in outward drying potential (38 perms) as well as airtightness.

Intello Plus – A “smart” vapor retarder that provides a first class air barrrier for thermal insulation in roofs, walls and floors. It gives structural systems a previously unachievable degree of protection from structural damage (from condensation), even under extreme climatic conditions, due to its intelligent vapor retarding properties.

Tescon Vanna – Air sealing tape is a long-lasting, robust solution for building airtightness. Used to seal the air control membranes over our prefab panels on the exterior and interior side.

Tescon Profil – Same great airsealing, weather resistance, and vapor profile as Tescon Vana, but with a 3-split release backing to make airtight connections and waterproof seals at corners quickly and easily.

Roflex pipe gaskets – Creates durable and airtight seals around pipes, ducts and cables which pass through membranes, wood-based panels and other substrates.

How do 475 products help achieve the Zero House goals?

Zero net energy use – A building must be air-tight to be truly energy efficient, and the air-tightness products from 475 High Performance Building Supply help us to ensure that our building is free of costly leaks and that our air sealing will be durable and long-lasting.

Zero toxins – All Pro Clima tapes and membranes are free of solvents, VOCs and softeners

Other reasons for using 475 High Performance Building Supply products:

Waste – Most of the ProClima products are 100% recyclable

Workability – The membranes and tapes are very rugged, and don’t stretch or deform. They are much easier to install than other house wrap and vapor retarders, and it is easy to install without waves or folds. The tapes adhere extremely well and can be applied smoothly and accurately.

Moisture control – All the products have top ratings for moisture control in their intended locations, and together allow us to safely create a vapor permeable wall, roof and floor assembly.

Durability – The membranes and tapes are long-lasting, and the excellent moisture control characteristics help the building to last a long time in a wide variety of humidity and weather conditions.

Any drawbacks to using 475 High Performance Building Supply products:

475 recently added a Canadian warehouse, so shipping times are greatly reduced. Products must be ordered directly from 475.

Many products do not have Canadian code compliance documentation, so even though they outperform conventional options, builders may have to use Alternative Compliance pathways to get code approval

Air sealing materials from 475 High Performance Building Supply are a key part of the high performance and energy efficiency of our projects at Endeavour. It is our hope that more builders will turn to these top-notch products in the move toward more energy efficient buildings.

What are Inline Fiberglass windows? Inline is a Toronto-based manufacturer of high quality, energy efficient windows that use fiberglass frames, rather than the more typical vinyl or wooden frames.

Where are Inline Fiberglass products used in Zero House? All of our windows and doors are manufactured by Inline, including casement windows, fixed windows, sliding glass doors and entry door with locks. To give you good quality glass products for your house or building you can visit Glass Replacement Visalia.

Range of plantation shutters have wide compound louvers that fit into a window frame and are controlled by way of a wooden rod running up the middle. When not needed, they swing away on hinges in the same way traditional shutters do, except on the inside.

How do Inline Fiberglass products help achieve the Zero House goals?

Zero net energy use – Inline makes very energy efficient windows with insulated fiberglass frames, triple glazing and great seals around opening windows. Inline received the highest energy efficiency rating in Canada from Energy Star. Inline worked with us to “tune” our glazing, so Zero House would have the best solar heat gain coefficient (SHGC) on the south glazing, and the best energy efficiency on the north.

Zero carbon footprint – The manufacturing process for fiberglass window frames has a much lower carbon footprint than vinyl windows, and is about the same as aluminum clad wood frames.

Zero toxins – Fiberglass windows do not off gas like vinyl windows, and do not require the often-toxic paints used to protect wood windows.

Durability – Fiberglass frames have very little expansion and contraction as temperature conditions change, which helps glazing units to maintain their seals. The windows do not deteriorate in UV light and do not require painting or maintenance.

Affordability – Inline windows are very reasonably priced, especially for their level of performance. The cost for the windows is easily justified by the increase in energy efficiency and energy savings.

Workability – The exterior extensions on the windows allow us to match our siding depth and create a good seal around the windows. Inline’s clip installation system is easy to work with.

Code compliance – Inline windows meet all required CSA standards.

Any drawbacks to using Inline Windows?

We have used Inline Windows on projects since 2005, and have never had any quality issues or call-backs.

We will definitely be using Inline Windows on future projects. When you want your house and windows painted, just hire house painting santa monica ca services.

This is one in a series of blog posts about the materials we’ve chosen to build our Zero House project…

What are GRK Fasteners? GRK makes a range of screw fasteners, including several lines of structural screws. Normal screws can’t be used in many building applications because they do not have the shear strength or the pull strength to be used for structural purposes. GRK Fasteners are strong enough to be used throughout a building, and feature a recessed star drive that doesn’t strip. They also have a ZIP-TIP and cutting pockets so they drive quickly and don’t require pre-drilling.

A 4-inch GRK RSS screw quickly drives and secures two prefab panels together

GRK fasteners hold the corners of each prefab panel together

Lifting straps for the wall panels are held with four GRK RSS screws

Even the large roof panels are held with four GRK RSS screws, which can be reused throughout the lifting process

Where are GRK Fasteners used in Zero House? The prefabricated panels used to build Zero House rely on GRK fasteners in many locations:

The RSS (Rugged Structural Screws) hold the corners of the prefab panels together, providing a strong connection that draws the top and side plates together reliably and offer the shear strength and pull strength to keep the panels together.

RSS are also used to connect the D-rings that allow us to pick up the panels with a crane or forklift.

RSS are then used to connect each of the panelized elements of the building to the adjacent panels.

The R4 Multi-Purpose Framing Screws are used to hold the strapping on the exterior of the building that will be used to attach the cladding. Here, their strength allows us to go through the outer layer of fiberboard and still make a good connection to the framing.

How do GRK Fasteners help achieve the Zero House goals?

Zero net energy use – RSS screws enable us to attach the prefab panels together with an exterior strapping that eliminates all thermal bridging from the design

Other reasons for using GRK Fasteners:

Affordability – Though GRK Fasteners are more expensive than some other fasteners, we are able to use fewer of them.

Availability – Home Depot and other major retailers carry GRK Fasteners

Workability – GRK screws never strip, drive quickly and without pre-drilling, cutting down on labor time.

Prefabrication – GRK screws allow us to quickly assemble our prefabricated panels, and then lift them into place on the building site.

This is one in a series of blog posts about the materials we’ve chosen to build our Zero House project…

What is Applegate Cellulose Insulation? Cellulose insulation is a high performance blown-in insulation for wall, roof and floor cavities that is made from recycled newsprint paper.

Where is Applegate Cellulose Insulation used in Zero House? Most of our prefabricated wall panels and all of our prefabricated floor and roof panels use Applegate cellulose insulation to pack the cavities.

Bags of cellulose are emptied into the hopper of the dense-pack blower

Cellulose is dense-packed to a density of 3.5 pounds per cubic foot

Once dense-packed, the cellulose fills all cavities

How does Applegate Cellulose Insulation help achieve the Zero House goals?

Zero carbon footprint – Applegate cellulose is made from recycled newsprint paper fibers, and that paper is about 50% carbon by weight. Rather than returning to the atmosphere as CO2 when the paper is burned or decomposes, it is now captured for long-term storage in the structure of our building.

Zero net energy use – Applegate cellulose has an R-value of 3.8 per inch, and adds R-62.7 to our floor system, R-38 to our walls and R-74 to our roof. The insulation is dense-packed into these cavities, ensuring that there are no gaps or voids in the insulation layer, which is key to high performance.

Zero toxins – Applegate cellulose is treated with borax as a fire retardant and insect deterrent. Though we wear respirators while applying the insulation, the material is not toxic and doesn’t contain the dangerous binders and fire retardants of most other insulation materials.

Other reasons for using Applegate Cellulose Insulation:

Affordability – Cellulose is the lowest cost option for cavity insulation, so we get all the sustainability benefits and a lower cost.

Code Compliance – Cellulose insulation is fully code compliant.

Workability – Dense packing cellulose is a very straightforward process, and a team of two can insulate a whole building in a day or two.

Waste – Because cellulose is blown into cavities, there are no off-cuts and no waste. Any cellulose left on site can be sent to newsprint recycling.

Vapor permeability – Zero House wall and roof systems are vapor-open, meaning that moisture is able to transpire through the entire wall or roof. Cellulose has a very high perm rating and moisture storage capacity, so is ideal for vapor permeable assemblies.

Any drawbacks to using Applegate Cellulose Insulation?

Dense-packing equipment may be difficult for owner-builders to rent. Most building-supply stores will provide the equipment for loose-blowing the insulation into attic spaces, but this isn’t adequate for dense-packing into walls.

Applegate Cellulose Insulation is a material that will definitely be used on further projects at Endeavour Centre.

This is one in a series of blog posts about the materials we’ve chosen to build our Zero House project…

What is SonoClimat Eco4? SonoClimat is an insulating sheathing board made from 81% recycled waste wood fibers. It comes in 1/2-inch and 1-1/2-inch thicknesses.

Where is SonoClimat Eco4 used in Zero House? The 1-1/2-inch version is used as exterior sheathing on all of the prefabricated wall and roof panels for Zero House.

SonoClimat Eco4 exterior insulated sheathing board

SonoClimat panels are 1-1/2 inches and are very easy to work with

One wall panel with the SonoClimat sheathing is ready for installation

SonoClimat provides the thermal break (R-4) for the exterior panels of Zero House

How does SonoClimat Eco4 help achieve the Zero House goals?

Zero carbon footprint – SonoClimat is made from recycled waste wood fibers, which are about 50% carbon by weight. Rather than returning to the atmosphere as CO2 when the wood fibers are burned or decompose, that carbon is now captured for long-term storage in the walls of our building.

Zero net energy use – SonoClimat Eco4 has an R-value of 4, and applied over the framing of our panels provides an important thermal break between the framing and the exterior atmosphere.

Zero toxins – The binder for SonoClimat is non-toxic and contains no volatile organic compounds (VOCs).
Most conventional buildings would use a foam insulation product in this position in the building, but the foam would have a high carbon footprint and many toxins we do not want to include in the building.

Other reasons for using SonoClimat Eco4:

Vapor permeability – Zero House wall and roof systems are vapor-open, meaning that moisture is able to transpire through the entire wall or roof. SonoClimat has a very high perm rating, so is ideal for exterior sheathing use with natural insulation materials like straw and cellulose.

Affordability – SonoClimat is about the same price as un-insulated exterior sheathing (OSB or plywood), but saves money and time because one product is both the structural and insulated sheathing, you can always get financial support from Rhinosure if your run short on money. We get all the sustainability benefits without paying more.

Waste – Off cuts from SonoClimat are fully recyclable.

Code Compliance – SonoClimat products have good testing data available to support their use as structural sheathing.

Workability – SonoClimat can be cut with standard job site tools and fastened with conventional screw or nails. Cap nails (with an integrated washer) are the best option.

Any drawbacks to using SonoClimat Eco4?

Though the product is available through most building supply stores, it is usually a special order item and not regularly stocked.

Care must be taken when fastening the sheathing as it is easy to over-drive nails into the surface

The edges of the panels were not always even between the laminations

SonoClimat Eco4 is a material that will definitely be used on further projects at Endeavour Centre. For the type of prefabricated panels used on this building, it is an ideal option, combining low cost, easy workability, structural and insulative properties with vapor permeability.

This is one in a series of blog posts about the materials we’ve chosen to build our Zero House project…

What is ReWall EssentialBoard? ReWall is a sheathing board made from recycled, compressed drinking cartons. It can be used for interior and/or exterior sheathing over frame walls.

Where is ReWall used in Zero House? All of our prefabricated wall and roof panels use ReWall EssentialBoard as the interior sheathing.

ReWall sheets looks a lot like drywall

ReWall sheets are used as structural sheathing on Zero House panels

A closeup reveals the layers of compressed, recycled drinking cartons

The “naked” version of ReWall clearly shows the shredded, recycled drinking cartons

How does ReWall help achieve the Zero House goals?

Zero carbon footprint – ReWall is made from 100% recycled paper fibers, and that paper fiber is about 50% carbon by weight. Rather than returning to the atmosphere when the paper is burned or decomposes, it is now captured for long-term storage in the walls of our building.

Zero net energy use – ReWall has an R-value of 1 for a 1/2-inch thick sheet, much better than other sheathing options like drywall or plywood.

Zero toxins – ReWall is made from 100% recycled drinking cartons, with no added glues or binders. Only food-grade materials go into the product, and there is no off gassing. EssentialBoard also scores a 10/10 on mold resistance.

Other reasons for using ReWall EssentialBoard:

Affordability – ReWall costs the same as conventional drywall and OSB sheathing, and much less than plywood, so we get all the sustainability benefits without paying more.

Code Compliance – ReWall products have good testing data available to support their use as structural sheathing.

Workability – ReWall can be cut with standard job site tools and fastened with conventional screws or nails.

Waste – ReWall can be fully recycled (though not all recycling centres will accept the material).

Any drawbacks to using EssentialBoard?

No local distribution means that shipments must be arranged direct from the factory in the US.

The sheets are “bendy” when being handled, so it can require two people to manage a sheet.

It was a bit difficult to make trim cuts close to the edge of the sheet as the saw would fray the material rather than making a clean cut.

There was a slight variation in thickness between sheets, which didn’t matter for our application but could present some difficulties if we were trying to use EssentialBoard as the finished sheathing and were mudding and taping the joints.

ReWall EssentialBoard is a material that will definitely be used on further projects at Endeavour Centre. Hopefully the product will start to receive wider distribution and will become available in more regions.

The Zero House project has three key goals: zero net energy use, zero toxins and zero carbon footprint. This blog will look at the notion of zero carbon footprint, and we’ll explore how Zero House will in fact far surpass this goal through carbon sequestration in building materials.

The notion of the embodied carbon footprint of buildings has not received much attention in the past. Even now, it’s not a consideration within any of the major green building rating systems and is not a key goal in very many sustainable building projects. But if climate change is a concern, addressing the embodied carbon within building materials may be the most important issue a designer or builder can address.

During the harvesting, processing and manufacturing of building materials, there are always greenhouse gas (GHG) emissions associated with these activities. Fuel is consumed, chemical processes unleashed and resources expended to create any building material. However, some materials have very high GHG emissions and others are very low. Typically, materials processed using a lot of heat and/or electrical energy will have higher embodied carbon than those with less intensive processing requirements. Good examples of this can be found in the open-source database called Inventory of Carbon and Energy Version 2.0, which provides amalgamated data for a wide range of building materials. Companies are also starting to produce Environmental Product Declarations (EPDs) that are third party analyses of a range of environmental impacts of particular products, including embodied carbon.

Calculating a building’s carbon footprint involves figuring out the weight of each material and then applying the appropriate embodied carbon factor. This will result in a tally of all the carbon emissions associated with a building. By this reckoning, Zero House has an embodied carbon footprint of 6.991 metric tons of CO2-e (which includes carbon dioxide emissions and other types of emissions expressed as units of CO2) emissions for this 1,000 square foot (92.9 m2) building. This is about 75.25 kg of emissions per square meter. This compares very favourably with the same house built to typical code standards, which would emit 134.8 kg per square meter. That’s a 56 percent reduction, which alone would be worthy of notice.

However, there is another side to carbon emissions and buildings. If a building uses plant-based materials in its construction (wood, straw, hemp, cork, bamboo, mycelium and recycled fibres of all kinds), those materials are partially made of carbon that has been taken from atmospheric CO2 and converted by the plant into its cellular makeup. Usually, the carbon in plants is released back to the atmosphere when the plant decomposes (or burns). But if we contain that plant fibre in a building for a long time, we sequester that carbon in the building. It’s the simplest form of carbon capture and storage (CCS); the plants do all the work of pulling CO2 out of the air, and we put them into buildings for a long time.

Wood framing

Cork sheathing from Jelinek Cork

Straw bale insulation

Wood fibreboard sheathing from MSL

ReWall EssentialBoard sheathing

Cellulose insulation from Applegate Insulation

Zero House uses a wide range of carbon sequestering materials. In fact, the shell of the house only uses three materials that do not sequester carbon. We can tally up the amount of carbon sequestered in materials by calculating the weight of each material, factoring in the average carbon content (the Phyllis database is a good source for this). Most plants contain 40-50% carbon by weight. When this carbon is released to the atmosphere as CO2, two oxygen molecules are added to each carbon molecule, so we multiply the weight of the carbon by 3.67 to find the weight of CO2 that is being sequestered.

Calculation spreadsheet for the embodied carbon of Zero House

As the table shows, the Zero House sequesters a lot of carbon: 32.26 metric tons of CO2 are effectively bundled up in this building! This offsets the embodied carbon footprint and we end up with a net sequestration of 25.26 metric tons. While a lot of this sequestration is in wooden materials, about half of what’s sequestered is in the form of “waste” fibres (straw, recycled wood fiber, recycled drink cartons, recycled newsprint, cork) that would have otherwise cycled directly back into atmospheric CO2.

This approach has great potential to help the building industry fight climate change. If all residential buildings were to take this approach, the 200,000-ish houses we build in Canada every year (at an average size of about 2,200 square feet) we’d be sequestering around 1.1 million metric tons of CO2-e per year. Add other building types (commercial and industrial) into the mix, and the construction industry could lead Canada in carbon sequestration.

With a “negative” carbon footprint from inception, Zero House also takes a zero net energy approach that will ensure that it has a tiny amount of operational carbon footprint over its lifetime. We’ll examine that in our next look at the Zero House goals…

One of the most exciting developments in the field of sustainable building is the use of biological processes to literally grow building materials. While experiments in this realm abound, the folks at Ecovative is one of the first to become available. Currently Ecovative is focused on packaging materials and other non-construction uses for Mycofoam, but its use as a building material is supported by a number of ASTM tests that show it to be a feasible building insulation material (see data sheet below). We are very excited to be an early adopter of this technology! We get all of our construction equipment at scaffolding equipment carlin nv.

This spring, we acquired some bags of Ecovative’s Grow-It-Yourself material to experiment with forming our own building insulation panels. We are happy with the results, and will be casting some larger panels to be used on our Zero House project.

Grow-It-Yourself kits of Mycofoam arrive as bags of agricultural waste fiber that have been innoculated with the mycelium spores.

The class prepares to start the grow-it-yourself process with several bags of material

Flour and water are added to the bags to kick start the mycelium growth process

The Zero House is designed to have zero net energy use, zero carbon footprint and zero toxins. But it is also designed to be completely prefabricated and modular! It features prefab wall panels, floor panels and roof panels that can be fabricated off site and assembled quickly. Prefabrication allows many benefits, including controlled conditions for construction, ease of construction and affordability.

A wall panel is framed, using the floor panels as a platform

ReWall EssentialBoard sheathing is made from 100% recycled beverage containers. It is used on the interior face of all our wall panels.

SONOclimat ECO4 sheathing boards are used on the exterior side of many of the panels. They are made from recycled wood fibers and offer R-4.

The Sustainable New Construction student team is currently assembling the wall panels for Zero House. We are exploring a number of wall systems:

Double stud with cellulose insulation

– This wall type is the most conventional approach, featuring:

2×4 frame construction

Cellulose insulation from Applegate Insulation. Cellulose insulation is made from recycled newsprint and offers excellent carbon sequestration and is non-toxic, while providing excellent thermal and moisture handling properties.

MSL SONOclimat ECO4 wood fiber board on the exterior side. Fiber board is made from recycled wood fibers, for excellent carbon sequestration and non-toxicity. The 1.5-inch boards (which come in 4×8 and 4×9 foot sizes) offer an R-value of 4. The product has a perm rating of 25.9 perms, meeting our requirements for a vapour-open wall assembly.

ReWall EssentialBoard on the interior side. EssentialBoard is made from 100% recycled beverage containers, for excellent carbon sequestration and non-toxicity. The 1/2-inch boards (which come in 4×8 and 4×9 foot sizes) and meet code requirements for structural sheathing.

This wall assembly is 12-inches thick and offers a total R-value of R-40.

Double stud with wool insulation

– This wall type features:

2×4 frame construction

Wool insulation from Living Rooms. Wool is not a common insulation in North America, but has a reasonable market share in the UK and Europe. Carbon sequestering, renewable and non-toxic, wool has an excellent R-value of 4 per inch and handles moisture well.

Cork sheathing board on the exterior side. Cork is a renewable resource that is carbon sequestering and non-toxic, and is impervious to moisture. It offers R-4 per inch, and we are using 2-inch thick sheets.

ReWall EssentialBoard on the interior side. EssentialBoard is made from 100% recycled beverage containers, for excellent carbon sequestration and non-toxicity. The 1/2-inch boards (which come in 4×8 and 4×9 foot sizes) and meet code requirements for structural sheathing.

This wall assembly is 12-inches thick and offers a total R-value of R-42.

Prefab straw bale with fiber board

Straw bale insulation. Straw is a locally available resource, composed of the dry stalks from grain crops (wheat straw, in this case). Straw is a renewable resource with remarkable carbon sequestering capacity, a good insulation value and is non-toxic with excellent moisture storage capacity.

MSL SONOclimat ECO4 wood fiber board on the exterior side. Fiber board is made from recycled wood fibers, for excellent carbon sequestration and non-toxicity. The 1.5-inch boards (which come in 4×8 and 4×9 foot sizes) offer an R-value of 4. The product has a perm rating of 25.9 perms, meeting our requirements for a vapour-open wall assembly.

ReWall EssentialBoard on the interior side. EssentialBoard is made from 100% recycled beverage containers, for excellent carbon sequestration and non-toxicity. The 1/2-inch boards (which come in 4×8 and 4×9 foot sizes) and meet code requirements for structural sheathing.

A small amount of cellulose insulation from Applegate Insulation provides a tight fit between the straw and the sheathing materials. Cellulose insulation is made from recycled newsprint and offers excellent carbon sequestration and is non-toxic, while providing excellent thermal and moisture handling properties.

This wall assembly is 17-inches thick and offers a total R-value of R-39.

Prefab straw bale with Mycofoam sheathing

Straw bale insulation. Straw is a locally available resource, composed of the dry stalks from grain crops (wheat straw, in this case). Straw is a renewable resource with remarkable carbon sequestering capacity, a good insulation value and is non-toxic with excellent moisture storage capacity.

Mycofoam insulation from Ecovative on the exterior side. Mycofoam is an insulation made by growing mycelium (the roots of mushrooms) in a mixture of agricultural waste fibers. This material is one of a number of exciting developments in the field of growing building materials. Using natural processes that happen with a minimum of inputs, this type of insulation offers extremely low ecosystem impacts, carbon sequestration and a great R-value of R-4 per inch. It is natural non-toxic and fire resistant.

Wall EssentialBoard on the interior side. EssentialBoard is made from 100% recycled beverage containers, for excellent carbon sequestration and non-toxicity. The 1/2-inch boards (which come in 4×8 and 4×9 foot sizes) and meet code requirements for structural sheathing.

This wall assembly is 17-inches thick and offer a total R-value of R-41.

The panels are currently under construction, and being stored until the whole building is ready for assembly. Stay tuned for more blog posts…

Thatch roofs may seem like a romantic and foreign notion in North America, but they are entirely feasible in a wide range of North American climates. No other roofing is annually renewable, carbon-sequestering and non-toxic. A thatch roof may not be for everybody, but it’s worth considering…

Thatch roof basics

Applications for system

Basic materials

How the system works

Harvesting phragmites from side of highway

Cleaning reed bundles

Bundles awaiting installation

Completed thatch roof

Seventh year of snow!

While it may seem strange for modern builders to think that a bunch of dried grass stems can provide a thoroughly water-resistant and long-lasting roof, thatch roofs have a long and successful history across a wide range of climatic zones. Thatching techniques have been developed worldwide, adapting the basic principle to suit available materials and to work in specific climates. Modern thatched roofs are installed in almost every region of the world, though in relatively small numbers.

The system of thatching used in many wet and/or cold climates involves fastening bundles of long, thick reeds or straw to the roof strapping in successive courses, each overlapping the preceding course. The thatch is laid at a thickness (which can range from 8–20 cm / 3–8 inch) that prevents water from working its way through the layers. Thatched roofs have very steep pitches to aid in this drainage.

Traditional thatch was hand-tied to the roof strapping using twine or rope. Modern thatchers often use screws and wire to provide attachment. Regardless of regional variations in material and technique, the thatch is held in place by securing a horizontal member across the thatch and tying that member back to the strapping through the thatch. The next course of thatch then covers the tie point as the roof is built upward. At the edges of the roof, the thatch is laid at a slight angle to encourage runoff to leave the edge of the roof and to provide a consistent appearance.

Thatching on flat sections of roof is relatively straightforward, but the same cannot be said for ridge, hip and valley sections. These areas take considerable knowledge and experience to execute in a weather-tight and long-lasting manner.

Many modern installations use a fire-resistant (often fiberglass) membrane under the roof strapping to prevent the spread of a fire from inside the building to the roof. Eavestroughs are not typically installed with thatched roofs, making them incompatible with rainwater harvesting.

Tips for successful installation

Thatching methods vary widely with the type of thatch material being used and the tradition of thatching used in the region. Ensure that the reed or straw being used is compatible with the climate and the installation technique.

Be sure you are able to obtain the material and expertise required to create a thatched roof. It is a rare type of roofing in North America, and must be well researched before deciding to proceed.

Plans for a thatched roof must be properly detailed before construction. The uncommon thickness of the roofing, the steep pitch required and the particular details at hips and valleys must be incorporated into the drawings to ensure the roof will work when built.

Dormers, hips and valleys require much more skill than simple gable roofs

Pros and cons of thatch roofs

Environmental impacts

Harvesting — Negligible to Low. Thatch that is harvested regionally will have the lowest environmental impact of any roofing material. The plants that produce useful thatch are annual grasses, making it the only annually renewable roofing. Some reeds that are suitable for thatching do not need to be manually seeded, but occur naturally on marginal lands that are otherwise not suitable for agriculture and aren’t sprayed or treated in any way. Most modern grain plants have been bred to have much shorter, narrower stalks than their genetic ancestors and are not suitable for thatch, but less common grains (spelt, rye, etc) still have stalk lengths and diameters that may work for thatch. Farmed grains may have environmental impacts associated with the use of herbicides and/or pesticides.

Manufacturing — Negligible to Low. Thatch requires little to no processing other than cutting, cleaning and bundling. These processes are done on a small scale and with minimal machinery and fossil fuel input. There are no toxic by-products created.

At the most intensive, a thatch roof will use a small amount of metal wire and screws and a layer of fiberglass matting that has high energy input and some toxic by-products. At the least intensive, round wood strapping and natural fiber twine is used.

Transportation — Negligible to High. Some thatch projects in North America are completed using thatch imported from Europe, because there are no commercial suppliers on this continent. This adds high transportation impacts to an otherwise low-impact roof. Many thatch roofs are made with locally, manually harvested material, keeping impacts very low.

Installation — Negligible. Thatch is largely installed without the use of power tools and does not create any problematic waste or by-products.

Embodied energy & carbon

Waste

Compostable — All reed or straw thatching, natural fiber twine.

Recyclable — Polypropylene twine, metal wire.

Landfill — Fiberglass matt offcuts, if used. Quantities can be negligible to low.

Energy efficiency

Historically, thatched buildings relied on the fairly significant amount of air trapped in the thatch to insulate the roof of the building. However, thatch allows for a lot of air infiltration and would not be considered adequate insulation or airtight enough to meet codes or modern comfort levels on its own. Modern buildings with thatched roofs rely on an insulation layer independent from the roof sheathing.

A thatch roof can have some beneficial effects by reducing summertime warming of the attic space quite significantly. Thatch roofs will also eliminate the issue of condensation on the back side of the roof sheathing as the material will not have the low surface temperatures of more dense sheathing and is able to adsorb and absorb moisture without condensation.

Labor input

Working at heights to install roofing has inherent dangers. Proper setup and safety precautions should always be taken when working on a roof.

Thatch roofing is unique in that, for most North American builders, harvesting the material is likely to be a necessary preliminary step. While suitable materials are widely available, harvesting and preparing them can be a very labor-intensive process, easily requiring more hours than the installation itself. In areas of the world where thatch material is harvested commercially and available for delivery to a job site, the labor input is obviously much lower.

Thatching is the most labor-intensive form of roofing. An experienced thatch crew can move at a speed that approaches that of an experienced cedar shingle crew. Beginners will move a great deal slower, as the process of laying thatch is very particular and must be done accurately and correctly.

Skill level required for the homeowner

Thatching requires a good deal of skill. In European countries, it takes many years of apprenticeship and experience to obtain the title of “Master Thatcher.” Beginners are advised to start with a very small roof, such as a small shed, and to keep roof shapes to simple gables or sheds. Hips and valleys add a lot of complexity to the thatching process, and should be left to those with plenty of experience.

Sourcing/availability

Both the material and the expertise to build a thatch roof can be difficult to source in North America. A few master thatchers practice in the U.S. and they tend to import their thatch material from Europe.

A homeowner wishing to attempt a thatch roof will have to resort to harvesting thatch material locally and learn from books or by taking workshops with experienced thatchers and bringing the skill back home.

Durability

Thatch roofs are surprisingly durable. In northern European climates, they can last for forty to eighty years. Depending on the style of ridge cap used, the ridge may need repair or replacing every ten to twenty years. A thatched roof at the end of its lifespan is not typically replaced; rather new thatch is built over top of the existing thatch.

Code compliance

No building codes in North America address the use of thatch roofs. Proposing a thatch roof will likely require a fair bit of documentation and persuasion, as there are few examples of thatched roofs on which a code official can base an assessment. The historical and modern use of thatch in Europe means that a lot of code-related testing and documentation exists to support it. A building department may be willing to consider a thatch roof with the right amount of documentation and some assurance that the installation is being done properly. The few master thatchers working in North America have been able to have their work approved, as have a small number of owner-builders.

Future development

There is no reason for thatch to be disregarded in North America, as it is a viable, durable roofing option that is remarkably environmentally friendly. As the costs of conventional roofing materials rise with the price of fuel to make them, thatch will start to look better and better. The machinery required to mechanically harvest and bundle thatch is not complicated or expensive, and viable thatch material grows in many places on the continent. There will always be limitations to the use of thatch roofing in urban areas, as fire safety concerns would limit the density of thatched roofs. But there are many locations where thatched roofs are feasible, appropriate and the best possible environmental choice. It will take many dedicated homeowners willing to push the boundaries and create a market in which thatch may start to take the kind of foothold where it creates a viable niche market, similar to cedar shingles.

How does it rate?

Resources for further research

Billett, Michael. The Complete Guide to Living with Thatch. London: Robert Hale, 2003. Print.

Composting Toilet Basics

Composting toilets collect urine and feces — referred to as humanure in the rest of this chapter — and treat it completely on-site, until it is transformed into useful compost or humus.

This category of treatment system does not include common pit outhouses, which do not provide ideal conditions for the conversion of humanure to compost, though given enough time the material in a pit toilet can undergo this transformation.

There are three common types of composting toilet:

Bucket toilet

Self contained composting toilet

Remote chamber composting toilet

Bucket toilet — This low-tech version of the composting toilet uses a bucket or similar portable receptacle placed under a seat/container to receive humanure deposits. Sawdust, wood shavings, chopped straw or another form of cellulose material is used to cover each deposit in the toilet, helping to reduce odor, absorb urine and provide aeration. Once full, the bucket is emptied into an outdoor compost heap. Here the material is layered and mixed and covered with more cellulose material, providing the right conditions for the natural conversion to compost/humus.

The indoor toilet construction is usually provided with passive or active ventilation, but no water connection or flushing action is used.

Self-contained toilet — These units provide a seat over an integral composting tray in a single, self-contained structure. Humanure deposits are received in the tray and provided with the appropriate conditions for composting action within the unit. These toilets all use some form of mechanical ventilation to reduce odor. Excess urine may require a separate handling system, or heat may be used to speed evaporation. Due to limited storage capacity, these toilets normally use some form of mechanical action and/or acceleration for the composting process and are only suitable for low numbers of users or for intermittent use.

The compost tray is removed from the unit when processing is complete or when the tray is full. It is often necessary to have an outdoor compost heap to receive material from these units, as it can prove difficult to complete the composting process within the unit.

Some models of self-contained toilet use chemicals or high heat to “cook” the humanure into a benign state. The material from these toilets is not useful compost, as the biological activity that creates rich, useful soil has been killed off.

Remote chamber toilet — A toilet (dry chute or low-water flush) sits above a large, enclosed chamber that receives humanure. The chamber is of sufficient capacity and design to contain and process a high volume of completed compost.

Units handle humanure in various ways. Some use heat and/or evaporation to rid the chamber of excess urine and water and speed the composting process, while others retain and process all material. Mixing or stirring capabilities, misting sprayers and rotating trays are options offered by certain manufacturers. Vacuum flush, allowing the toilet to be level with or below the height of the chamber, is also available. With this type of toilet you will definitely need a plumber at some point to do pipe rehabilitation

Some units gather excess urine after it has passed through the bulk material in the chamber and retain this liquid as a high-quality fertilizer. This makes best use of the potential value of all material entering the toilet, as up to 80 percent of the nutrient value in toilet waste is in the urine. Once transformed into nitrites and nitrates after passing through the biologically active compost solids, the liquid can be a safe and low-odor fertilizer.

All chamber-style toilets provide humanure with enough time and adequate conditions to fully convert to compost before being removed from the unit. These are the only units that do not require additional outdoor composting capacity.

Basic bucket toilet

Humanure compost system

Stand-alone composting toilet

Vacuum flush toilet

Remote chamber compost tank

Remote chamber composting tanks

Types of waste handled

– Black water (though most systems are waterless)

Tips for successful installation

Understand the maintenance requirements of any type of composting toilet before committing to installation. All require some maintenance, and dealing with humanure is not for everybody. Some units require infrequent maintenance, others daily.

Check local codes before planning for a composting toilet. They are an accepted solution in some codes but not in others.

Check local codes for the legal status of composted humanure. Though a good deal of documentation exists to show the material is biologically benign, some jurisdictions require compost to be treated as hazardous waste.

Some types of composting toilets require specific layout arrangements that must become part of the home design.

Mechanical ventilation is part of most composting toilets, requiring an exit tube that passes through the roof of the building with as straight a run as possible.

Plan for an easily accessible route from the point of removal to the outdoors, to facilitate emptying of the toilet or chamber.

Be sure there is sufficient provision on the property for units requiring outdoor composting facilities, and that the process of finishing humanure compost outdoors is well understood.

When using commercially produced units, follow the manufacturer’s instructions for successful installation.

Pros and cons

Environmental impacts

Composting toilets are the only form of toilet that does not treat human excrement as waste, and rather as a potentially regenerative material for amending soils and fertilizing plants. A large environmental problem is thereby transformed into a solution to soil depletion, creating more robust growing environments.

The composting of humanure is not without issues, and untreated or partially treated material can be contaminated with pathogens that are potentially dangerous to humans and animals and can contaminate soil and ground water. There is a growing body of evidence that complete composting of humanure is relatively easy to accomplish reliably, but the correct conditions must be understood and created.

Material costs

Simple bucket toilets and appropriate outdoor composters can be built for as little as a hundred dollars. Complete remote chamber toilet systems can cost between four and eight thousand dollars.

Labor input

Depending on the type of composting toilet, labor input can vary greatly. Other toilets do not require direct ventilation, and even the simplest composting toilet has more components and longer installation times than a conventional flush toilet.

Skill level required for the homeowner

Maintenance — Moderate to Difficult. Some form of regular maintenance is inevitable with composting toilets. Bucket toilets can require daily maintenance to transfer full buckets to the compost pile. Chamber units may only need monthly inspections and annual emptying.

Sourcing/availability

There are many commercially available self-contained and remote chamber toilets. These are typically sold directly from the manufacturer or in specialty shops. Bucket toilets are homemade, with plans readily available online or in books.

Plumbing for any composting toilet system are standard components available through any plumbing supply outlet.

Durability

The simpler the toilet system, the greater the durability. Units with heaters and moving parts are more prone to durability issues. Consider the accessibility of parts that may need repair or replacement; if they are in difficult locations (especially if they require emptying of the toilet’s contents) they will be unpleasant to service.

Future development

Interest in composting toilets is just beginning to grow, and the technology is likely to develop rapidly in coming decades. There has been a significant shift in understanding about humanure, from a sense of revulsion and the certainty of contamination and illness to an appreciation of the simplicity and value of composting. It will be some time before this shift affects a broad constituency of builders and homeowners, but the research and experience currently being gained in this field by early adopters will be valuable contributions to a technology that is potentially transformative. There is little else in home-building practice that could so radically improve the environmental impacts of our homes.

Resilience

Build and operating a composting toilet system in a low- or no-energy scenario is straightforward. The bucket toilet is an excellent example of resilient technology, as it not only replaces an energy- and resource-intensive practice, but does so in a way that gives back valuable nutrients to the ecosystem.